Gas Turbine Flapper Valve Fairing for Vibration Control
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Solution Overview
Problem
Flapper valves in gas turbine engines experience premature failure due to constant vibration caused by flickering, which results from vortex shedding and turbulence, leading to potential loss of flow control function and structural damage.
Innovation Solution
A valve assembly with two independently movable flappers and a fairing between them, where the fairing is aerodynamically designed to form a streamlined body with the flappers in the open position, minimizing vortex shedding and turbulence, and acting as a stopper to constrain the flappers, reducing flickering and flow pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If flappers are made thin to reduce weight and improve flow control, then the valve assembly weight decreases and flow control improves, but the flappers become more susceptible to vibration and premature failure
Solution Approach 1:
A fairing is introduced as an intermediary component between the two flappers. This fairing acts as a protective mediator that reduces the direct impact of turbulent flow and vortex shedding on the flappers, thereby protecting thin flappers from excessive vibration while maintaining their lightweight design and flow control functionality.
Solution Approach 2:
The fairing provides beforehand cushioning by being positioned upstream of the flappers to absorb and dissipate turbulent flow energy before it reaches the flappers. This pre-protection reduces the vibrational forces acting on the flappers, allowing them to be made thinner without compromising durability.
2Speed
If flappers are made thin to reduce inertia and improve response time, then the valve response speed increases, but the flappers experience more severe flickering and vibration
Solution Approach 1:
The fairing serves as an intermediary that mediates between the turbulent flow and the thin flappers. It reduces the intensity of vortex shedding and turbulence before the flow reaches the flappers, allowing thin flappers to achieve fast response speeds without being subjected to severe flickering and vibration.
Solution Approach 2:
The fairing provides beforehand cushioning by being positioned upstream to absorb turbulent flow energy before it reaches the flappers. This pre-protection enables thin flappers to respond quickly to flow changes while minimizing the harmful effects of vortex shedding and turbulence.
3Device complexity
If no fairing is used to simplify the device structure, then the device complexity decreases, but flow pressure loss increases and flapper vibration worsens
Solution Approach 1:
The fairing acts as an intermediary component that, while adding some structural complexity, significantly reduces flow pressure loss by streamlining the flow path and reducing turbulence. The fairing's presence between the flappers creates a more efficient flow pattern that minimizes energy losses.
4Manufacturing precision
If flappers are positioned close together to improve flow control precision, then the flow control function improves, but the flickering phenomenon intensifies due to increased interaction between flappers
Solution Approach 1:
The fairing serves as an intermediary that reduces the direct interaction and mutual interference between the two closely positioned flappers. By being disposed between the flappers, it dampens the flickering phenomenon that intensifies when flappers are close together, while still allowing precise flow control through the narrow gap between the flappers.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The streamlined fairing design reduces flapper vibration, increases resistance to wear, and ensures smooth, non-turbulent flow, thereby enhancing the durability and performance of the valve assembly by minimizing flickering and flow pressure loss.
Implementation Method 1
Flickering is a phenomenon where the flow condition includes phenomenon such as vortex shedding and turbulence around the flappers
Implementation Method 2
Flickering is a phenomenon where the flow condition includes phenomenon such as vortex shedding and turbulence around the flappers
Implementation Method 3
flowing the air along the substantially streamlined body
Data Source
AI summary
A valve assembly for a gas turbine engine comprising two flappers movable independently from one another between an open position and a closed position; and a fairing disposed between the two flappers. The fairing has a portion extending downstream of the two flappers. The portion is a downstream portion of a substantially streamlined body. The two flappers are movable relative to the fairing, and when in the open position, the two flappers abut the fairing and form an upstream portion of the substantially streamlined body. A method of flowing air through a valve assembly for a gas turbine engine is also presented.